Device for the reduction of kinetic energy of bullets from cartridge ammunition

ABSTRACT

A device, which may be either incorporated into the original barrel of a gun or into a subcaliber barrel for installation in a prefabricated gun, comprises an expansion chamber located immediately downstream of the cartridge opening. Upon firing of the gun, the expansion chamber is available to receive a portion of the combustion gases thereby reducing the momentum of the bullet leaving the cartridge.

United States Patent [1 1 Seitz 1 Sept. 24, 1974 DEVICE FOR THE REDUCTION OF KINETIC ENERGY OF BULLETS FROM CARTRIDGE AMMUNITION [76] Inventor: Georg Seitz, Am Bruchkamp 2,

3301 Watenbuttel, Germany [22] Filed: June 5, 1973 [21] Appl. N0.: 367,126

[52] US. Cl. 42/76 R, 42/77 [51] Int. Cl F4lc 21/00, F4lc 21/10 [58] Field of Search 42/76 R, 76 A, 77, 75 B;

[56] References Cited UNITED STATES PATENTS 2/1938 Guthrie 42/77 10/1962 Rosebush 42/76 R 11/1968 Gronemann 42/76 R 3,696,748 10/1972 Picairtl cl ul 42/76 R FOREIGN PATENTS OR APPLICATIONS 384,058 12/1932 Great Britain 42/77 Primary Examiner-Benjamin A. Borchelt Assistant Examiner-C. T. Jordan Attorney, Agent, or FirmBrowdy and Neimark 5 7 ABSTRACT 6 Claims, 2 Drawing Figures DEVICE FOR THE REDUCTION OF KINETIC ENERGY OF BULLETS FROM CARTRIDGE AMMUNITION The present invention relates to the reduction of kinetic energy of bullets from cartridge ammunition and, more particularly, to a device for reducing the danger of a firearm by providing means which may be incorporated into the firearm to reduce the kinetic energy of bullets fired from such firearm.

BACKGROUND OF THE INVENTION Various locales have different arms control laws. In certain locales, for example, private ownership of firearms is limited to firearms in which the projectiles or bullets have a relatively low velocity. For example, in the Federal Republic of Germany, the kinetic energy of the bullet leaving the end of the firearm determines, under the arms law and safety-technical regulations, the measure of the dangerousness, or conversely the safety, of the firearm; and in accordance with the new Federal Arms Law in the Federal Republic of Germany, the kinetic energy of the bullets leaving the barrel must now not exceed more than 0.75 kpm.

With firearms which use cartridge ammunition, as is most common, the velocity of the bullet leaving the barrel is determined by, above all other matters, the nature of the cartridge, e.g., the weight and composition of the propellant and the weight and nature of the bullet. With regular firearms, where the bore is formed in such a way that the cartridge chamber merges with the barrel after a short conical passage, the kinetic energy of the bullet leaving the barrel can be influenced only in a very limited manner, e.g., by varying the length of the barrel. Furthermore, in the past where such a variation was desired, it was normally to increase, rather than decrease, the kinetic energy of the bullets thereby upgrading the normal effect of the ammunition.

Now, however, in view of the various firearms laws which are becoming more common, it has become desirable to provide means of reducing the kinetic energy ofthe projectile leaving the gun barrel so that its value remains below a designated value established by the particular law and safety-technical regulations. There are, however, a number of difficulties involved since the reduction of kinetic energy only makes sense if the precision of the shot is not adversely affected, something which is not guaranteed by extreme shortening of the gun barrel.

Certain attempts have been made to reduce kinetic energy of bullets fired from prefabricated guns. However, this has been accomplished by the use of subcaliber barrels which are installed in the prefabricated guns. These subcaliber barrels are effective to reduce kinetic energy of bullets fired only in a very limited manner, namely by the use of smaller cartridge ammunition. In other words, there has already appeared on the market subcaliber barrels and cartridge chambers with which it is possible to fire cartridge ammunition from a firearm in which the bullets receive a lesser kinetic energy than with the bullets of the original ammunition.

Such subcaliber barrels have been used primarily in shotguns which use ball ammunition. However, subcaliber barrels and shells have also been installed in rifles so as to expend a bullet of smaller caliber or, with the subcaliber cartridge chambers, to expend a bullet of the same caliber but with a lesser weight. These subcaliber barrels and cartridge chambers are of the same gauge as the regular firearm so that the kinetic energy is also determined by the design of the bullet which is intended for the subcaliber barrel or the cartridge chamber.

While the use of such subcaliber barrels or cartridge chambers have been useful to an extent, they have not been satisfactory for the purposes of the present invention, since even when using the regular commercial cartridge with the lightest charge, the kinetic energy of the bullet leaving the firearm or small caliber barrel is above the value which has been established by certain regulations. The manufacture of special low-power ammunition is expected to be not entirely suitable since too large a dispersion of thrust and irregularity and accuracy of the projectile from such low power ammunition is to be expected.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to overcome the defects of the prior art.

It is another object to provide for improved and safer use of firearm weapons at low projectile speeds.

It is another object of the present invention to provide a device for the reduction of kinetic energy of bullets from cartridge ammunition.

It is another object of the present invention to provide a device for the reduction of kinetic energy with the use of regular fixed ammunition without impairing the accuracy of the shot.

It is another object of the present invention to decrease the kinetic energy of regular ammunition to a value below that set up in legal regulations.

These and other objects and the nature and advantages of the instant invention will be more apparent from further reading. The velocity of bullets with a given barrel diameter and bullet weight is, above all, determined by the time curve of the gas pressure and, specifically, by the maximum developed gas pressure. The maximum gas pressure which a particular charge develops is dependent upon the area which is at the disposal of the powder gases. Since in the first approximation the co-volume of the powder gases can be equated with the specific volume of the true powder, it results that with high charge density, which is present with the fixed ammunition, the area available to the powder gases in the cartridge is very small. However, with the use of smokeless powders, a high charge density is required, since the consumption of the powder is a function of the gas pressure, and so to achieve uniform combustion the pressure must increase veryquickly after ignition. The further development of pressure is most dependent upon the combustion rate of the powder and the size of the chamber which is open to the powder gases in the course of movement of the bullet after departure from the cartridge.

In accordance with the present invention, there is provided an expansion chamber which is located in the barrel at the opening of the cartridge chamber, the expansion chamber providing space into which the powder gases flow after the shot has been fired. By provision of such an expansion chamber the kinetic energy of the shot can be controlled to a large degree and the degree of influence on the shot is related to the size of the expansion chamber.

BRIEF DESCRIPTION OF THE DRAWING For a better understanding of the invention, possible embodiments thereof will now be described with reference to the attached drawing, it being understood that these embodiments are intended as merely exemplary and in no way Iimitative.

FIG. 1 is a cross sectional view of a first embodiment in accordance with the present invention; and

FIG. 2 is a cross sectional view of a second embodiment in accordance with the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS Referring to FIG. 1 there is shown a portion of a firearm 10 having a one piece barrel 12. At the upstream end of the barrel 12 is located, as is conventional, a cartridge chamber 1 adapted to receive a cartridge of given size, the bullet or projectile of which is so sized as to pass through the bore 2 of the barrel 12 in accrodance with common practice.

In accordance with the present invention a cylindrical expansion chamber 3 is generally located between the cartridge chamber 1 and the main portion of the barrel bore 2, the expansion chamber 3 beginning at the location 4 corresponding to the opening of the cartridge placed within the cartridge chamber 1. The expansion chamber 3 has a diameter of IO 50 percent greater than the diameter of the barrel bore 2, and a length of from 1 to 5 times that of the diameter of the barrel bore 2.

Referring to FIG. 2, there is shown a second firearm having a barrel 12'. As with the embodiment 10 of FIG. 1, the firearm 10' has a cartridge chamber 1, and expansion chamber 3' beginning at the location 4 ofthe opening of the cartridge placed within the chamber 1, and a bore 2 of size corresponding to that ofthe projectile of the cartridge placeable in the cartridge chamber 1.

However. the expansion chamber 3' of the firearm 10' in FIG. 2 is somewhat different from that described above in relationship to the embodiment 10 of FIG. 1. Thus, the expansion chamber 3' has the shape of a frustro-cone with the diameter decreasing or tapering from a maximum at the location 4 to a minimum at the juncture downstream with the barrel bore 2. As with the embodiment of FIG. 1, the expansion chamber 3' has an average diameter 10 to 50 percent larger than the bore 2 and a length of l 5 times the caliber of the bore 2. It should be understood that while the taper in the illustrated embodiment 10' is rectilinear or straight, it may also be curvilinear.

FIG. 2 also shows another feature which may be utilized regardless of the shape of the expansion chamber 3 or 3', and this feature is particularly suitable for the conversion of already existing firearms. Thus, the expansion chamber 3' may be incorporated in a subcaliber barrel 14 for permanent installation into a firearm having a barrel 12' which would normally fire bullets with a high kinetic energy. By means of a permanent connection, such as one using hardened steel pins 16, the subcaliber barrel 14, preferably formed of a softer material, cannot be removed from the original barrel 12. In addition, the feature of using hardened steel pins 16 with a softer subcaliber barrel 14 also guarantees that the cartridge chamber cannot be bored out since the drill will run freely. Through this kind of installation of the special subcaliber barrels, a firearm which is to be used only for short range target practice or as a collectors item or decorative firearm, can be changed in such a way that it can shoot projectiles at a low kinetic energy.

By means of the device of the present invention, the ignition and the initial combustion of the powder from the cartridge takes place uniformly and safely. By the time the bullet leaves the cartridge chamber 1, the gas pressure achieves a valve which is sufficient to guaranty a regulated combustion of the powder. Since an additional space in the form of the expansion chamber 3 or 3 is then immediately available for expansion of such gases, the pressure increase and, therefore, the combustion rate of the powder is reduced and the momentum ofthe projectile bullet is decreased. In this manner it is possible, in accordance with the present invention, to reduce the kinetic energy of the bullet to the desired extent and at the same time guaranty uniformity of the pressure curve and the bullet momentum.

The use of a subcaliber barrel. such as exemplified in FIG. 2 constitutes a preferred embodiment of the present invention. Through the installation of a subcaliber barrel including a suitable expansion chamber, a regular firearm can be changed in such a way that although it can be fired, the kinetic energy of the bullet is decreased so that the altered firearm corresponds to legal requirements, e.g., a kinetic energy of less than 0.75 kpm. in the Federal Republic of Germany. This method has significance for the alteration of live firearms into display and collectors firearms and the subcaliber barrel can be secured in such a way that nothing can be seen from the outside. However, these firearms can still be loaded, aimed and fired to demonstrate certain features of the firearm, without the firearm being excessively dangerous.

While subcaliber barrels of prior constructions were able to accomplish some reduction of kinetic energy due to the use of smaller cartridges compared with the original ammunition, the value of the kinetic energy in the use of such prior devices was still determined by the cartridge in the subcaliber barrel. By means of the use of the expansion chamber, on the other hand, a further reduction of the kinetic energy of the bullet is achieved and only this change reduces the kinetic energy of the bullet to a value less than that determined by the size of the cartridge.

It is to be understood that the invention is not limited to the embodiments disclosed which are illustratively offered and that modifications may be made without departing from the invention.

What is claimed is:

1. In a device for the reduction of the kinetic energy of a bullet of cartridge ammunition in firearms having a barrel, comprising a barrel portion having fixedly formed therein a cartridge chamber and a bore downstream from said cartridge chamber through which the bullet from said cartridge passes, the improvement comprising:

an expansion chamber fixedly formed in said barrel and located between said cartridge chamber and said bore and beginning at the location corresponding to the opening of the cartridge in said cartridge chamber, said expansion chamber having an average diameter of 10 50 percent greater than the diameter of said bore and a length of l 5 times that of the diameter of said bore.

bore are all incorporated in a subcaliber barrel.

5. A device in accordance with claim 4, wherein said subcaliber barrel is formed of a softer material than the material of the firearm barrel.

6. A device in accordance with claim 5 wherein said subcaliber barrel is located within the firearm barrel and is connected thereto with hardened steel pins. 

1. In a device for the reduction of the kinetic energy of a bullet of cartridge ammunition in firearms having a barrel, comprising a barrel portion having fixedly formed therein a cartridge chamber and a bore downstream from said cartridge chamber through which the bullet from said cartridge passes, the improvement comprising: an expansion chamber fixedly formed in said barrel and located between said cartridge chamber and said bore and beginning at the location corresponding to the opening of the cartridge in said cartridge chamber, said expansion chamber having an average diameter of 10 - 50 percent greater than the diameter of said bore and a length of 1 - 5 times that of the diameter of said bore.
 2. A device in accordance with claim 1 wherein said expansion chamber is cylindrical.
 3. A device in accordance with claim 1 wherein said expansion chamber is tapered from a maximum diameter adjacent said cartridge chamber to a minimum diameter adjacent said bore.
 4. A device in accordance with claim 1 wherein said cartridge chamber, said expansion chamber, and said bore are all incorporated in a subcaliber barrel.
 5. A device in accordance with claim 4, wherein said subcaliber barrel is formed of a softer material than the material of the firearm barrel.
 6. A device in accordance with claim 5 wherein said subcaliber barrel is located within the firearm barrel and is connected thereto with hardened steel pins. 